Rocket system and method



y 1966 w. F. EVERETT ETAL 3,252,281

ROCKET SYSTEM AND METHOD Filed Sept. 17, 1962 4 Sheets-Sheet 1 I 66 64 I 46 I J T I 32 3 3 r O 6 P70 T '& .A 4

1N VENTORS WILLARD F. EVERETT IJ'OHN E COPELAND OQAAYOQHAX ATTORNEYS y 4, 1966 w. E. EVERETT ETAL 3,252,281

ROCKET SYSTEM AND METHOD 4 Sheets-Sheet 2 Filed Sept. 17, 1962 0 0 4 0 m m u w m %Wo X Elia E E 7 H 3 2 l m w m m m ,m ZH W I INVENTORS WILLARD E EVERETT JOHN E. COPELAND ATTOR NEYS FIG. 10

y 1966 w. F. EVERETT ETAL 3,252,281

ROCKET SYSTEM AND METHOD I I w ms I I I II I' IIIII I I III I I .IIIIIIIII .II III I I 1.

INVENTORS WILLARD F. EVERETT I 5 JOHN E. COPELAND T TO R NEYS "IIIIII' IIIIII y 24, 1966 w. F. EVERETT ETAL 3,252,281

ROCKET SYSTEM AND METHOD 4 Sheets-Sheet 4 Filed Sept. 17, 1962 FIG. 9

INVENTORS WI LLARD F. EVERETT JOHN F. COPELAND BY 9 %CL-L6 L 0% ATTORNEYS United States Patent 3,252,231 ROCKET SYSTEM AND METHOD Willard F. Everett, Hagerstown, and John E. Copeland,

Sharpshurg, MIL, assignors to Fairchild Hiller Corporation, a corporation of Maryland Filed Sept. 17, 1962, Ser. No. 223,918 7 Claims. (Cl. fill-35.6)

The present invention relates to rocket propulsion in general and more specifically to a steam rocket and launcher therefor.

Fuels used as propellants to drive rockets have varied from ordinary gun powder to the so-called exotic fuels of recent years. Rocket efficiency depends largely upon the type of fuel used as a propellant. One of the criteria upon which efficiency is based is that of specific impulse which is a number indicating the pounds of thrust obtained per second of burning time per pound of fuel. Very high specific impulses of from 250-300 have either been achieved or are theoretically possible using certain of the exotic fuels as, for example, fluorine and liquid hydrogen. However, the high cost of the fuel necessary to achieve these high fifi'lClfillClCS together with the complex associated structure and equipment needed for handling these usually dangerous fuels add greatly to the overall cost of the rocket system.

Although many applications require the highest specific impulses obtainable, many applications exist for relatively inexpensive rockets which do not require very high specific impulses. Two primary uses for such rockets are as sounding rockets first, to gather upper atmosphere data for use in weather prediction and second, to make upper atmosphere or near space flight tests of instruments or components for space vehicles. Rockets presently used for these purposes, however, are still quite costly. Efforts to date to improve this situation have been directed toward improving the specific impulse of the fuels and the mass ratio, to thereby put up larger payloads with smaller rockets. While this approach may be sound for the larger payload-higher altitude missions, it is an uneconomical approach for a number of applications. The fuels used to achieve higher specific impulses, even the solid propellants, have become more expensive and burn at' higher temperatures posing serious material selection problems for the casing and the rocket nozzle and also making the ground handling problems more severe.

Since many rocket missions can be accomplished by using specific impulses of approximately 100, the present invention provides a rocket propulsion system using preheated, pressurized water, which is inexpensive and usually readily available, in combination with an inex- 1 pensive fuel which is burned for added heat energy to produce a relatively inexpensive steam rocket having a specific impulse of better than 100 and a total impulse greater than the steam alone or the burning fuel alone that is admirably suited for such missions. In this invention, briefly, the water is heated to above its boiling point at sea level, atmospheric pressure and preferably to about 635 F. in a tank seperate from the rocket itself. The water is heated at constant volume and pressurized to a pressure above that of atmospheric and preferably to about 2000 pounds per square inch after which it is transferred from the separate tank to the rocket. As a practical matter, the high temperature and high pressure for the water should be, respectively at least about 545 F. and 1000 pounds per square inch pressure and it may be possible to operate with the water at a peak temperature of 705 F. and at 3206 pounds per Patented May 24, 1966 of combustion are added to the water preferably by burning a fuel, such as a solid propellant, to thereby increase the total impulse and substantially reduce the comibustion chamber and nozzle temperature.

The general object of this invention is to provide a thrust generator and method adaptable to the propulsion of vehicles generally comprising creating a confined mixture of steam and products of combustion of a burning fuel and expanding the mixture through a nozzle.

A more specific object of the invention is to confine a high temperature 'high pressure body of water within an enclosure which may be a rocket casing and burn a fuel, preferably in solid form, within the enclosure in a manner to effect the admixture of the products of combustion with the Water to increase its heat energy and finally to discharge the resulting steam in admixture with the gaseous products of combustion through a nozzle to propel the enclosure.

A more specific object of the invention is to provide an inexpensive steam rocket using heated and pressurized water expanded to atmospheric pressure to produce thrust by the escaping steam which action is augmented by the addition of heat energy resulting from the admixture of the heated products of combustion of burning fuel.

Still another object is to produce such thrust as a continuing action while the rocket is in flight.

Another object of the invention is to provide an apparatus by means of which such steam rocket can be charged with preheated high temperature pressurized water.

Still another object of the invention is to provide a novel method of generating propulsive thrust in accordance with the above described principles.

Other and more detailed objects of the invention will be apparent from the following description of the several embodiments thereof selected for illustration in the accompanying drawings and hereinafter described.

In those drawings,

FIGURE 1 is an elevat-i-onal view, partly in section, and with some parts broken away, illustrating a rocket assembly in accordance with this invention, mounted in a launching tube and associated with means for preheating and pressurizing the water with which the rocket is initially charged;

FIGURE 2 is an enlarged vertical central cross-sectional-view of the portion of the assembly of FIGURE 1 which involves supplying the water to the rocket and the means for restraining the rocket during charging;

FIGURE 3 is a cross-sectional view taken on the line 33 of FIGURE 2;

FIGURE 4 is a cross-sectional view taken on the line 4'4 of FIGURE 2;

FIGURE 5 is an enlarged longitudinal central crosssection-al view of the rocket of FIGURE 1;

FIGURE 6 is a similar view with some parts broken away of a modified form of rocket structure including means for increasing the rate of heat transfer from the products of combustion of the burning fuel to the water content of the rocket;

FIGURE 7 is a cross-sectional view taken on the line 77 of FIGURE 6;

FIGURE 8 is an elevational view of a further modified rocket construction with some parts in cross-section and some parts broken away;

FIGURE 9 is a longitudinal central cross-sectional view, with some parts broken away, of still another form of rocket construction;

FIGURE 10 is an elevational view with some parts broken away and some parts in cross section of a modified form of rocket in accordance with this invention as applied for propelling ground vehicles.

The nature and scope of this invention will become apparent as the various embodiments thereof illustrated in the drawings are described in detail.

Thus in FIG. 1 the rocket is generally indicated at 1%) illustrated as mounted Within the launching tube 12 with which is associated the ground charging equipment. The launching tube is supported by a derrick-like tower structure 14- which supports the tube in a vertical position. It is noted, of course, that the launching tube and its supporting structure may be adapted to aim the tube at other than vertical angles in order to launch the rocket on various desired initial trajectories. In addition, of course, the supporting structure could be mounted on mobile equipment for some uses.

The launching tube 12, as illustrated, is in the form of a long tube of cylindrical cross-section and is provided at its lower end with a housing which could be called a breech structure forming, in any event, a hollow expansion chamber 18. Within the tube 12 is a piston bore rider adapted to slide along the internal wall of the tube during launching. Preferably, and as shown in FIG. 4, the rider 20 consists of four equiangular segments 22 having their upper surfaces shaped to form a seat on Which the rocket may rest. These segments in turn rest upon an internal shoulder 24 forming part of the launching tube. The particular rocket illustrated is provided with four conventional tail fins 25 arranged at the aft end of the rocket.

As shown in FIG. 3 the launching tube has a pair of internal radially extending arms and 32 positioned below the shoulder 24 on which the aft end of the rocket 19 seats (see also FIG. 2). The tail fins 26 rest at the lower ends on the annular shoulder 28 in the region of the union of the launching tube 12 with the breech casing 16. As further illustrated in FIG. 4 provision is made where interference might occur so that the fins 26 may assume this position. The rocket is provided with a tail nozzle 38 and the ends of the radial arms 30 and 32 are shaped to form the annular passage 36 through which the nozzle may be moved in either direction.

A locking assembly is provided to hold the rocket thus seated during charging. This assembly is shown in complete detail in US. Patent No. 2,613,961 issued to J. E. Westcott on October 14, 1952. It will be described herein in sufiicient detail for the purposes of adequate disclosure. The assembly includes a pair of opposed gripping blocks 40 and 42 having frusto-conical gripping faces 44 and 46 arranged to form a combined complementary frusto-conical surface corresponding to the exterior surface of the nozzle 38 for the purpose of encircling and gripping the nozzle. A toggle block 48 has a central tongue 50 which fits into the bifurcated end of the block 42 and is ivotally joined thereto by the pivot pin 52. The blocks 40 and 42 are pivotally mounted on a pair of parallel tie plates 54 and 56 by means of pivot pins 58 and 60 respectively to form a toggle linkage (see FIGS. 2 and 3). The radial arm 32 is slotted at 62 to receive the tripping lever 64 which is pivotally mounted therein on the pin 66. Attached to the lower end of the tripping lever 64 is a pull cable 68 which extends externally of the tube 12 through the opening 70. The trip lever 64 is provided with an angular seat 74 positioned to engage the roller 72 mounted on the pin 60.

Th upper end of the tripping element is shaped to provide a camming surface 76 for coaction with the roller 72. When it is desired to release the rocket the cable 68 is pulled causing the tripping lever 64 to rotate in a counter-clockwise direction on the pin 66. The camming surface 76 pushes downwardly on the roller 72 which displaces the toggle block 48 in a clockwise direction breaking the toggle linkage to thereby release the gripping blocks 40 and 42. This releases the nozzle 38 and of course the rocket to which it is attached.

The ground equipment for charging the rocket casing with high temperature pressurized water includes a cylindrical tank 78 of suitable capacity. This tank can be heated in any suitable manner, for example, by means of a plurality of standard electrical strip heaters mounted on its exterior and supplied from any suitable electrical power source.

Electrical heating is preferred because of its convenience, economy and adaptability to mobile assemblies. Of course, other sources of heat suited to the purpose could be used. The supply end of the tank 73 is connected by a conduit 32 containing the control valve 104 to the nozzle 33 by means of a fitting in the form of a converging nozzle 86 (see FIG. 2). The pipe 82 passes into the expansion chamber 18 through an opening 84 in the wall of the breech structure 16. The end of the nozzle 85 is shaped to form a fluid tight connection with the converging-diverging rocket nozzle 38.

Water is supplied from any suitable source through the conduit 38 to a pump P which delivers the water under pressure into the right hand end of the tank 78 through a control valve 94 and coupling 92. The pump can also discharge into the left hand end of the tank 78 through a bypass line 96* having a control valve 96. The interior of the tank 78 is divided into two parts by means of a movable piston 98. A bypass vent line 1019 containing the control valve 102 connects the left hand end of tank 78 with the conduit 82 beyond the control valve 104. The purpose of this bypass line is to pre-pressure the conduit 82 and the chamber of the rocket before the main valve 194 is opened to prevent explosive shock to the rocket which would otherwise attend the full opening of the main valve 104.

The water which is to be used to charge the rocket at high temperature and high pressure is supplied to the left hand side of the piston 98. This is done by opening the valve 96 after which it is closed. When the water thus accumulated in the tank 78 is brought up to temperature and pressure valve 94 is opened so that piston 93 is moved to the left to force the water from the tank 78 into the rocket casing.

The internal construction of one form of rocket is illustrated in FIG. 5. The rocket casing 198 is provided with a nose cone 1% of suitable size and shape for carrying the payload depending upon the purpose of a particular flight. As diagrammatically illustrated, a nose cone can be a separate part of the casing 138 and can be attached thereto in any suitable manner not shown. The casing can be constructed of various materials including metals and plastics depending upon its intended use. It is shown as being circular in cross-section but can be obviously shaped in any manner suited for the intended use and related to good aerodynamic efiiciency. As shown in FIG. 5 the aft end of the casing 168 is provided with the converging diverging nozzle 38 and the tail fins 26 previously referred to.

Within the casing 168 is mounted a central longitudinally extending preferably cylindrical standpipe 110. The lower end of the standpipe is connected to the entrance of the nozzle 33 and its upper end is formed into a bell month 111 attached to the end of the casing 108 by means of struts 113. Mounted on the standpipe and surrounding it is a housing 112 forming a fuel chamber for a ring or rings of solid rocket propellant fuel 114. The housing 112 is preferably circular in cross-section and concentric with the standpipe and is closed at its upper end as shown and open at its lower end as shown. The lower end is supported on the standpipe and braced therefrom by means of a plurality of spoke-like radial arms 116. The braces 113 and the supports 116 preferably have a streamline cross-section from top to bottom to minimize the drag that would impede fluid flow. As a result of this arrangement the standpipe provides a cylindrical space 114 surrounded by the cylindrical space 119 between it and the housing 112. An outer cylindrical space 117 is formed between the housing 112 and the casing 108.

Operation of acceleration-deceleration test sleds.

When the rocket is charged with high temperature pressurized water as previously described, it fills the chambers 115 and 117 and a part of the chamber 119. Air trapped between the water and the end of the fuel rings 114 in the space 118 prevents the water from wetting the fuel.

Before describing the operation of this rocket the other forms illustrated herein will be described. The first of these forms is illustrated in FIGS. 6 and 7. As before, the rocket has the casing 108 with the standpipe 110 and the housing 112. The fuel rings 114 are used as before. The main difference in this construction over the previous one is the provision of the radially and longitudinaliy extending heat exchange fins 120 mounted on the interior surface of the housing 112. Mounted on the exterior of the housing 112 are a series of annular heat exchange fins 121. The function of these fins will be described later.

The second modification is illustrated in FIG. 8. In this modification the structure of FIG. 5, and if desired FIG. 6, is provided with an additional concentric housing 122, .the end wall 124 of which is mounted on the interior surface of the casing 108. This housing extends longitudinally in the annular chamber 117 as shown and its end wall is provided with a plurality of vent openings 130. The other end of the housing 122 is complementarily shaped with respect to the internal curved annular abutment 103a of the casing to define the flow path of fluid inthat region as indicated. The other difference is that the upper end of the standpipe 110 is flared into a somewhat larger bell mouth 132 as shown.

The final modification of the rocket is illustrated in FIG. 9 in which case the standpipe 110 is replaced with a cylindrical fuel casing 134- closed atits upper end and provided with a converging nozzle 140 at its lower end. The fuel is diagrammatically illustrated at 148 and at 136 and 138 are a series of radial spoke-like bracing arms for supporting the casing 134 centrally within the casing 108. An expansion chamber 142 is provided by a reentrant annular wall 144 which coacts with the nozzle end 140 to provide a restricted annular passageway 146 as shown. This arrangement of parts provides a jet pump which becomes active to draw water from the casing 108 into the expansion chamber 142 by reason of the discharge of the products of combustion of the fuel 148 through the nozzle 140 into the chamber 142. The entire mixture is discharged from that chamber through the nozzle 38 to propel the rocket.

Finally there is illustrated in FIG. an application of the steam rocket principles of this invention to provide thrust in a horizontal plane such as would be useful for example in propelling a ground vehicle at high velocity and accelerating the vehicle at such high velocity in a relatively short time.

A practical use for such an arrangement would be the Sleds, sometimes referred to as rocket sleds sliding along hori zontal rails are accelerated to very high speed in a short space of time and then brought to a stop by means of a water brake in a comparably short time. They are used extensively in various testing environment to determine the effects of high acceleration and deceleration.

Referring to FIG. 10, a portion of such a sled structure is diagrammatically shown at 154. Mounted on the sled is a pedestal block 156 to which is connected the lower end of a cylindrical casing 152 which tube is further supported by means of lugs 198 and 200 connected by a bolt 202. The upper end of the casing 152 is provided with a closure head 158 having the passages 160 and 162 therethrough to which are connected respectively a safety valve 164 and a pressure gage 166. Within the casing is a standpipe 168 open at its upper end and curved at its lower end into a horizontal extension 170 passing through the opening 172. This extension is provided with a control valve 176 and terminates in a converging-diverging exhaust nozzle 174.

The lower end of the casing 152 is sealed by means of a plug 178 having a central expansion chamber 180. This chamber is connected by a plurality of vent holes 182 with the water space 184 formed bythe casing 152. A cap 186 covers the vent holes 182 and remains in place until the rocket is fired to prevent water in the space 184 from entering the chamber 180 and thereby wetting the propellant fuel 190. This fuel is contained within a casing 188 extending through the base 156 and provided with a removable cap 191 for permitting the introduction of the fuel 190. A nozzle member 192 is interposed between the fuel and the chamber 180 and has a central opening forming a converging-diverging nozzle 193. Mounted on the casing 152 are a plurality of electric strip heaters 196 provided to heat water in the space 184.

The operation of the rockets of FIGS. 1 to 8 inclusive will be described first. In each of these it is necessary to use some means to charge the space within the rocket casing with high temperature pressurized water. By way of example, such rockets have been operated with water charged into the rocket casing at approximately 635 F. and a pressure of about 2000 pounds per square inch. This water can be termed saturated water under these conditions. Obviously, these temperatures and pressures are not critical and would be determined as those skilled in the art will understand from a number of factors including the weight of the rocket and the distance it is to be propelled. In order to charge the tank 78 with water in preparation for heating it, valves 102 and 104 (FIG. 1) are closed. Valve 96 is open and with the .pump P running'water can be pumped into the left side of the tank '78 to the desired pressure. The right hand end of the tank, if necessary, can be provided with a venting valve so that the piston 38 will be [forced .to the extreme right during this operation, valve 96 is closed and the strip heaters energized. The Water in the tank is then heated to the desired temperature with the rocket in the launching tube and the nozzles 38 and 86 thereby connected. Valve 102 can be opened to supply some steam to the rocket casing without shock. Valve 104 can then be opened together with valve 94 with the pump P running. Piston 98 will be gradually forced to the left by the discharge of the pump forcing all of the hot water to the left of the piston into the rocket casing under pressure. All valves are then closed.

The rocket casing is now full of saturated water at the desired temperature and pressure. The rocket is now charged and to launch it the cable 68 is pulled unlatching the locking device. Simultaneously therewith the solid propellant is ignited by conventional means not illustrated. The burning fuel generates hot products of combustion which are discharged into intimate mixture and heat exchange relation with the hot water. The hot gases generated have a temperature of approximately 4000 F. and thus are capable of transferring substantial amounts of heat energy to the already hot pressurized water. The mixture of water and hot gases is discharged from the rocket casing through the nozzle 38 and of course as the hot gases flash the water into steam, the discharging fluid is mainly a mixture of steam and the products of combustion of the fuel being discharged at high velocity from a condition at high pressure to the atmosphere.v Thus there is generated a thrust which propels the rocket forwardly. Those skilled in the art will realize that by predesigning the nozzle exit area and the propellant burning rate to a desired relationship, a constant boiling rate and water steam chamber pressure will result thereby producing a substantially constant thrust level for the period of propulsion.

Initially as the fluid expands into the chamber 18 of the breach structure its propelling force can be augmented if desired by a slightly different operation of the ground apparatus. Instead of forcing the heated water into the rocket housing by moving the piston 98, the transfer thereof from the tank 78 to the rocket housing can be effected solely by the creation of the pressure in the tank 78 as the result of applying heat thereto. Under these conditions, the initial propulsion of the rocket could be increased by opening valve 94 as well as valve 104 if it has been closed and pumping water under high pressure behind the piston 98 so that the hot water remaining at the left hand end of tank 78 will be discharged by nozzle 86 behind the bore rider 20 to create a thrust in addition to that being created by the discharge of the fluid from the rocket into the chamber 18. It will be recalled that at the initiation of the flight the rocket will have been released and the connection between the nozzles 38 and 86 broken. This operation can be arranged for by having the tank 78 of sufficient capacity and filling it with water and heating it to a temperature so that the charge delivered into the rocket will be at a predetermined temperature and pressure such as for example the suggested 635 F. and the 2000 pounds per square inch pressure. In other words, if things are properly arranged the rocket casing can be filled with the required quantity of water at the proper temperature and pressure by starting at higher levels it being noted that under these conditions the conduit 82 and the left hand end of tank 78 will be but continuations of the space within the rocket casing.

It is obvious, of course, that when the rocket is discharged from the launching tube the bore rider 20 will fall away in its segmented parts.

The operation of the rocket of FIG. 9 is substantially the same as that of the others except that the arrangement of parts provides for admixture of the products of combustion of the fuel 148 with the high temperature high pressure water in the casing 108 in the expansion chamber 142. The mixture of steam and gases is then discharged through the nozzle 38 to propel the launch forward.

The operation of the system in FIG. 10 is similar to the others except for certain changes for purposes of convenience and operating etficiencies since the unit is for ground operation and not intended for flight. Since weight is not a critical item, water is discharged into the rocket casing through the conduit 170 to the desired pressure, and valve 176 is then closed. The water is then heated to the desired temperature by the strip heaters 196. This does away with the ground equipment used in other systems.

Also, since the launch is intended for repeated use, frequently with short intervals of time between each use, the fuel chamber is placed in a more accessible position. When the propellant is ignited the hot gases pass from the combustion chamber 194 through nozzle 193 into expansion chamber 180 from which they pass through the openings 182 into the chamber 184. The pressure of the gas dislodges cap 186, the hot gases then pass into heat transfer relationship with the hot pressurized water and the mixture of steam and hot gases are expanded to atmosphere through the nozzle 174 with the valve 176 o en. Discharge from the nozzles propels the vehicle forward.

In order to further illustrate the utility of the present invention the following figures are set forth for a specific steam rocket that would meet the requirement of a specific mission which requires that a 12 pound payload be lifted to an altitude of 40 miles. A rocket constructed substantially as shown in FIGURE 1 having an internal diameter of casing of 10 inches and a length of 100 inches using 200 pounds of water at approximately 635 F. and 2000 pounds per square inch pressure and a solid propellant weight of 23.5 pounds having a thrust duration of 37.75 seconds (a propellant charge of 5 inches outside diameter and 2 inches inside diameter, 40 inches long) will reach an altitude of approximately 62,436 feet at thrust termination and a payload apogee altitude of 208,- 000 feet. If the rocket be constructed primarily of a plastic reinforced casing with a wrapping of fiber glass,

the weight of parts will be approximately pounds and the gross weight of the rocket will total approximately 315 pounds. A two-stage version of this steam rocket would satisfy another mission which requires that a payload of 25 pounds be lifted to an altitude of 440,000 feet.

Although the present invention has been illustrated and described as taking certain specific forms and configurasions it is to be understood that such forms and configurations are for purposes of illustration only of certain preferred embodiments and do not purport to suggest all the arrangements that would come within the scope of the invention.

What is claimed is:

1. A rocket system of the type described comprising a casing having a discharge nozzle at its aft end, means for establishing a body of water within said casing at a temperature substantially above the boiling point of water at atmospheric pressure and substantially above atmospheric pressure, combustion means in said casing for generating high temperature products of combustion Within said casing in heat exchange relation with said body of water, and means for commingling the products of combustion with said body of water, said last two means being located in said casing and up stream from the throat of said nozzle, said rocket being propelled by the escape of steam in admixture with said products of combustion through said nozzle.

2. In the combination of claim 1 said combustion means including an enclosure for a combustible fuel within the casing.

3. The combination of claim 1, means for facilitating the exchange of heat from the products of combustion to the body of water.

4. The combination of claim 1, means cooperating with said last two means to actively effect admixture of the products of combustion with the water.

5. The combination of claim 1, said first means including means for heating the water to a said temperature and pressure and means for transferring the Water to the rocket casing at said temperature and pressure.

6. In a steam rocket the combination of a rocket casing; means for storing energy within said casing in the form of water at high pressure and temperature, the said high pressure being substantially above atmospheric pressure and the said high temperature being substantially above the boiling temperature of water at atmospheric pressure; means for expanding said water to the atmos phere to convert the energy thereof to thrust; and means in said casing for simultaneously adding energy in the form of heat and the products of combustion of a fuel by admixture with said water prior to its expansion to the atmosphere to increase the total impulse.

7. In a steam rocket the combination of a rocket casing; means for storing energy within said casing in the form of water at high pressure and temperature, the said high pressure being substantially above atmospheric pressure and the said high temperature being substantially above the boiling temperature of water at atmospheric pressure; means for storing additional ener y within said casing in the form of combustible material; nozzle means for expanding said water to the atmosphere to convert the said energy to thrust; means for simultaneously burning said combustible material to release said additional energy; and means for adding said additional energy in the form of heat and gaseous products of combustion by admixture with said water prior to its expansion to the atmosphere to increase the total impulse.

References Cited by the Examiner UNITED STATES PATENTS 886,199 4/1908 Flaig 60-39.57 1,879,579 9/1932 Stolfa et al. 60-356 2,351,750 6/ 1944 Fawkes.

(Other references on foiiowing page) 9 UNITED STATES PATENTS Hoskins 6039.58 Casey.

Truax 60-356 X Fitzpatrick 6035.6 X

Barnes et a1. 891.7

1 0 FOREIGN PATENTS 334,657 10/1903 France. 477,022 6/1915 France.

5 MARK NEWMAN, Primary Examiner.

ABRAM BLUM, SAMUEL LEVINE, Examiners. 

1. A ROCKET SYSTEM OF THE TYPE DESCRIBED COMPRISING A CASING HAVING A DISCHARGE NOZZLE AT ITS AFT END, MEANS FOR ESTABLISHING A BODY OF WATER WITHIN SAID CASING AT A TEMPERATURE SUBSTANTIALLY ABOVE THE BOILING POINT OF WATER AT ATMOSPHERIC PRESSURE AND SUBSTANTIALLY ABOVE ATMOSPHERIC PRESSURE, COMBUSTION MEANS IN SAID CASING FOR GENERATING HIGH TEMPERATURE PRODUCTS OF COMBUSTION WITHIN SAID CASING IN HEAT EXCHANGE RELATION WITH SAID BODY OF WATER, AND MEANS FOR COMMINGLING THE PRODUCTS OF COMBUSTION WITH SAID BODY OF WATER, SAID LAST TWO MEANS BEING LOCATED IN SAID CASING AND UP STREAM FROM THE THROAT OF 